An object of the invention is to develop a centrifugal pump of the type stated at the outset in such a way that it has a particularly high efficiency and can be produced at a particularly favorable cost.
According to an aspect of the invention, this problem is solved by the fact that in each case at least one projecting annular web of the gap seal is arranged on the cover disk and on the housing part, and that the web of the housing part is offset relative to the web of the cover disk.
By virtue of this configuration, a flow leading from the intake duct to the outlet duct is guided along a particularly long path in the gap seal. Moreover, the flow undergoes a number of deflections as a result, leading to a particularly high restricting effect of the gap seal. By virtue of the high restricting effect of the gap seal, the centrifugal pump according to the invention has a particularly high efficiency. The webs are particularly simple to manufacture, and therefore the centrifugal pump according to the invention furthermore has particularly low manufacturing costs.
The webs could each be taken as far as the center of the gap seal, for example. However, according to another advantageous aspect of the invention, it helps to increase the number of deflections and increase the restricting effect of the gap seal if webs arranged opposite one another each project over half the height of the gap seal.
According to an advantageous aspect of the invention, the gap seal has a particularly high restricting effect if a plurality of chambers bounded by the webs in the gap seal has different cross sections. The different cross sections of the chambers in the gap seal lead to a number of changes in the velocity of the flow, leading to the restriction thereof.
According to another advantageous aspect of the invention, a particularly high restricting effect of the gap seal combined with particularly simple production can be achieved in a simple manner if the gap seal has respective annular ducts close to the intake duct and close to the outlet duct, the ducts being arranged perpendicularly to the plane of the supporting disk of the rotor, if the annular ducts are connected to one another by a transverse duct and if the webs project into the transverse duct. This configuration enables the components bounding the gap seal to be joined axially in a simple manner and manufactured at low cost, e.g. by injection molding. Moreover, this means that the gap seal is of stepped design, contributing to a particularly high restricting effect.
According to another advantageous aspect of the invention, the webs oppose the flow in the gap seal if the transverse duct connecting the annular ducts to one another slopes relative to the plane of the supporting disk of the rotor, and if the webs projecting into the transverse duct are arranged perpendicularly to the plane of the supporting disk of the rotor. The alignment of the webs relative to the transverse duct gives rise to high turbulence in the flow, ensuring that the gap seal has a particularly high restricting effect. Since the height of the rotor blades relative to the radially outer boundary of the rotor decreases in any case, this configuration furthermore leads to a particularly low consumption of materials and hence to particularly low manufacturing costs.
According to another advantageous aspect of the invention, a contribution to a further increase in the number of deflections of the flow and hence to the restricting effect in the gap seal is made if at least one of the annular ducts is connected to the intake duct or the outlet duct by a transverse duct. According to another advantageous development of the invention, the webs can be produced in a particularly simple manner during the manufacture of the components by injection molding if the webs taper toward the free end thereof. By virtue of this configuration, the cover disk and the housing can be produced in a simple manner during manufacture by injection molding. Particularly when the components are manufactured in large numbers, as is customary with motor vehicles, this leads to very low manufacturing costs. As a result, the manufacture of the webs and hence the production of the gap seal has a neutral effect on costs.
A contribution is made to a further reduction in the manufacturing costs of the centrifugal pump according to the invention if at least one of the components of the housing part or the cover disk is manufactured from plastic.